Sync with template-lint

Author: NullVoxPopuli

docs/rules/template-require-strict-mode.md

@@ -6,37 +6,52 @@
 
 Require templates to be in strict mode.
 
-Templates should use the strict mode syntax (template tag format) rather than loose template files. Strict mode templates (`.gjs` / `.gts` files) provide better integration with JavaScript and type checking.
+Ember's Polaris edition component authoring format is template tag, which makes
+templates follow "strict mode" semantics.
+
+This rule requires all templates to use strict mode (template tag). Effectively this
+means you may only have template content in `.gjs`/`.gts` files, not in `.hbs` or
+`.js`/`.ts`.
 
 ## Examples
 
 This rule **forbids** the following:
 
 ```hbs
-<div>
-  Hello World
-</div>
+// button.hbs
+<button>{{yield}}</button>
 ```
 
-(in a `.hbs` file)
-
-This rule **allows** the following:
+```js
+// button-test.js
+import { hbs } from 'ember-cli-htmlbars';
 
-```hbs
-Hello World
+test('it renders', async (assert) => {
+  await render(hbs`<Button>Ok</Button>`);
+  // ...
+});
 ```
 
-(in a `.gjs` or `.gts` file)
+This rule **allows** the following:
 
-## Why?
+```gjs
+// button.gjs
+<template>
+  <button>{{yield}}</button>
+</template>
+```
 
-Strict mode templates provide:
+```gjs
+// button-test.gjs
+import { Button } from 'ember-awesome-button';
 
-- Better integration with JavaScript tooling
-- Type safety in TypeScript projects
-- Clearer component boundaries
-- Easier refactoring and navigation
+test('it renders', async (assert) => {
+  await render(<template><Button>Ok</Button></template>);
+  // ..
+});
+```
 
 ## References
 
-- [Ember.js Guides - Template Syntax](https://guides.emberjs.com/release/templates/syntax/)
+- [Template Tag Guide](https://guides.emberjs.com/release/components/template-tag-format/)
+- [Strict Mode RFC](https://rfcs.emberjs.com/id/0496-handlebars-strict-mode/)

lib/rules/template-require-strict-mode.js

@@ -1,6 +1,10 @@
 const ERROR_MESSAGE =
   'Templates are required to be in strict mode. Consider refactoring to template tag format.';
 
+function isStrictModeFile(filePath) {
+  return filePath?.endsWith('.gjs') || filePath?.endsWith('.gts');
+}
+
 /** @type {import('eslint').Rule.RuleModule} */
 module.exports = {
   meta: {
@@ -24,16 +28,11 @@ module.exports = {
   },
 
   create(context) {
+    const filePath = context.getFilename ? context.getFilename() : context.filename;
+
     return {
       'GlimmerTemplate:exit'(node) {
-        // Check if the template is in strict mode
-        // Strict mode templates are in .gjs/.gts files
-        // Non-strict templates are in .hbs files
-
-        const filePath = context.getFilename ? context.getFilename() : context.filename;
-
-        // Only flag .hbs files as non-strict
-        if (filePath && filePath.endsWith('.hbs')) {
+        if (!isStrictModeFile(filePath)) {
           context.report({
             node,
             message: ERROR_MESSAGE,

tests/lib/rules/template-require-strict-mode.js

@@ -12,6 +12,10 @@ ruleTester.run('template-require-strict-mode', rule, {
       filename: 'hello.gjs',
       code: '<template>hello</template>',
     },
+    {
+      filename: 'hello.gts',
+      code: '<template>hello</template>',
+    },
   ],
   invalid: [
     {
@@ -25,7 +29,6 @@ ruleTester.run('template-require-strict-mode', rule, {
         },
       ],
     },
-
     {
       filename: 'hello.hbs',
       code: `<template><div>
@@ -51,13 +54,17 @@ const hbsRuleTester = new RuleTester({
 });
 
 hbsRuleTester.run('template-require-strict-mode', rule, {
-  valid: [
-    '<template>hello</template>',
-    `import Component from '@glimmer/component';
-
-  export default class HelloComponent extends Component {
-    <template>hello</template>
-  }`,
+  valid: [],
+  invalid: [
+    {
+      code: '<div>hello</div>',
+      output: null,
+      errors: [
+        {
+          message:
+            'Templates are required to be in strict mode. Consider refactoring to template tag format.',
+        },
+      ],
+    },
   ],
-  invalid: [],
 });